Github action: Install custom public key for PostgreSQL install

Author: joto

.github/actions/ubuntu-prerequisites/action.yml

@@ -7,7 +7,9 @@ runs:
     - name: Remove preinstalled PostgreSQL
       run: |
         sudo apt-get remove -yq postgresql*
-        sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list'
+        sudo apt-get install curl ca-certificates gnupg
+        curl https://www.postgresql.org/media/keys/ACCC4CF8.asc | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/apt.postgresql.org.gpg >/dev/null
+        sudo sh -c 'echo "deb https://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list'
         sudo apt-get update -qq
       shell: bash